RESUMO
BACKGROUND: Incompatibility of the major blood groups A, B, and O has been an absolute contraindication for heart transplantation. However, because of immunologic immaturity, infants may have relative protection from hyperacute rejection and thus could undergo transplantation with ABO-mismatched organs. METHODS: Since January 2000, the authors have adopted a policy of considering infants for ABO-incompatible heart transplantation. Serum isohemagglutinin titers were measured before, during, and after transplantation. Two infants (3 and 2 months old) and a 21-month-old child underwent ABO-incompatible heart transplantation. During cardiopulmonary bypass, plasma exchange was performed. No other antibody-removal procedures were performed. A routine immunosuppressive regimen was used, and rejection was monitored by endomyocardial biopsies. An additional two patients (31 and 18 months old) were worked up but were unsuitable for ABO-incompatible transplantation because of high isohemagglutinin titers. They were successfully bridged to transplantation and received heart transplants from ABO-compatible donors. RESULTS: All three infants with ABO-incompatible heart transplants are fit and well, 40 months, 30 months, and 12 months postoperatively. All three had serum antibodies to antigens of the donor's blood group before transplantation. No hyperacute rejection occurred. No morbidity attributable to the ABO incompatibility has been observed. CONCLUSIONS: ABO-mismatched heart transplantation may be undertaken safely and without any short-term adverse consequences in infants and young children in whom isohemagglutinin production is not yet established.